Conventionally known is a direct drawing apparatus (direct imaging apparatus) that draws and forms a desired circuit pattern or the like by performing continuous local exposure on a drawing target object such as a printed board, a semiconductor substrate, or a liquid crystal substrate (hereinafter also referred to simply as a “substrate”) by scanning the substrate with exposure light such as laser light.
The direct drawing apparatus performs drawing of a circuit pattern in accordance with drawing data, which is data converted from design data of the circuit pattern and described in a format that can be processed by the direct drawing apparatus. Although a substrate such as described above may undergo deformation such as warpage, contortion, or distortion that accompanies upstream processing, the design data is normally created without consideration given to such deformation. Thus, even if converted drawing data is used as is to draw a circuit pattern, it is difficult to achieve a satisfactory drawing quality due to, for example, misalignment with a previously formed circuit pattern, and an improvement in yield cannot be achieved.
Accordingly, with this type of direct drawing apparatus, it has been proposed to perform correction processing called local alignment in which the shape of a substrate targeted for drawing is measured in advance, displacements of points (hereinafter also referred to as “target points”) on the substrate are calculated from the obtained measurement result, and the drawing data is itself corrected so as to conform to the displacements, and to perform drawing using the corrected drawing data. In Japanese Patent Application Laid-open No. 2008-3441 (Document 1), correction amounts of target drawing data are calculated from position information of four vertices of a square surrounding the drawing data.
With the technique described in Document 1, since the correction amounts are calculated from the position information of the four neighboring points surrounding target drawing data, correction for local distortion of a substrate occurring in the vicinity of the drawing data is possible, but it is not possible to make precise correction in the case where distortion occurs over a larger area of a substrate, for example, if the entire substrate is distorted in an undulating manner.